You are being asked to take part in a research study of a new product called PMPA vaginal gel. The scientific name for PMPA is 9-[(R)-2-(phosphonomethoxy)propyl]adenine monohydrate. PMPA gel was made to see if it can prevent women from becoming infected with HIV, the virus that causes AIDS, through sex. Before studying whether PMPA gel prevents people from getting HIV, we must make sure that is safe for women to use. PMPA has been used safely in a small number of people given either orally (my mouth) or intravenously (IV through an arm vein). PMPA gel has not been tested in the vaginas of women. Up to 70 women will participate in this safety study. This study is being done in Philadelphia and Providence, Rhode Island. This research study includes 4 visits. These visits include a screening visit, an enrollment visit, a day 7 visit, and a day 14 visit. In addition, you may be asked to participate in a focus group visit. The tests and exams from the screening visit and the enrollment visit will determine if you can be in the study.